This message is harmless and can be ignored. It means that a request for data was sent to a peer you are already connected to. This is most common when there are few peers in the swarm for a given torrent. It does not affect your down or upload speed in any way.

1 Bittorrents logs file under UNIX, GNU/Linux operating systems are found under $HOME/.bittorrent/bittorrent-{cosole,curses}.log